The present invention relates to a silicone antifoaming agent composition excellent in the persistence of the foam controlling effect.
In various industrial processes involving a treatment step of liquid or a treatment step with liquid. foaming often presents a serious problem. That is, the foaming of liquid is causative of a reduction in the efficiency of the treatment or the quality of a product.
It is well known that an antifoaming agent having an effect of breaking foam. i.e., a foam breaking effect, or an effect of lowering the formability of liquid. i.e., a foam controlling effect is used in order to solve the problematic foaming of liquid. Particularly, a silicone antifoaming agent is favorable, because it is chemically stable, scarcely affects an object of the treatment process, and exhibits a relatively high antifoaming effect even in a minute amount.
Up to this time, there have already been known various silicone antifoaming agents, for example, silicone oils, viscous compounds comprising a silicone oil and a fine inorganic powder such as carbon black, alumina or colloidal silica (i.e., oil compounds). solutions of such a silicone oil or oil compounds in an organic solvent and oil-in-water emulsions prepared by the emulsification of such an oil compound with a surfactant.
However, these silicone antifoaming agents are poor in the persistence of the foam controlling effect. Accordingly, when a prolonged control of foaming is required, they cannot always satisfy the requirement sufficiently.